Porous monolithic ceramic bodies are finding expanded uses in various industrial applications as catalyst supports, filters, burner supports, and bioremediation supports. In these various applications, characteristics such as pore volume, pore size distribution, degree of open (reticulated) porosity, etc. are important to the performance of the monolithic ceramic body.
Various techniques have been used to make these monolithic bodies. For example, porous monoliths have been formed by partial sintering of shaped ceramic powder compacts. In other methods, foams have been used to generate porosity in a green ceramic body which is then fired to preserve porosity corresponding to the foam cells. Another method has been proposed in German patent application 40 33 626 whereby thin ceramic membranes are formed by coagulation of a polymer ceramic mixture in a precipitation bath.
These various methods have one or more disadvantages such as inability to form porous bodies having narrow pore size distribution, inability to form three dimensional bodies, inability to produce adequate reticulated porosity, inability to adequately control pore size, etc. The partial sintering method can produce porous three dimensional bodies, but the bodies usually have limited reticulated porosity. The foam methods can be used to make bodies with higher porosity, but the pore size and pore size distribution can be difficult to control especially if a narrow distribution of pores of less than 100 .mu.m are desired. The coagulation method presents difficulties in forming three dimensional bodies of uniform porosity.
Thus, there is a need for new and improved methods of forming porous monolithic ceramic bodies.